/***************************************************************************

    hashing.c

    Hashing helper classes.

****************************************************************************

    Copyright Aaron Giles
    All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are
    met:

        * Redistributions of source code must retain the above copyright
          notice, this list of conditions and the following disclaimer.
        * Redistributions in binary form must reproduce the above copyright
          notice, this list of conditions and the following disclaimer in
          the documentation and/or other materials provided with the
          distribution.
        * Neither the name 'MAME' nor the names of its contributors may be
          used to endorse or promote products derived from this software
          without specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY AARON GILES ''AS IS'' AND ANY EXPRESS OR
    IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
    WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    DISCLAIMED. IN NO EVENT SHALL AARON GILES BE LIABLE FOR ANY DIRECT,
    INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
    (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
    SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
    HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
    STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
    IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
    POSSIBILITY OF SUCH DAMAGE.

***************************************************************************/

#include "chdtypes.h"

#include "hashing.h"
#include "zlib.h"


//**************************************************************************
//  CONSTANTS
//**************************************************************************

const crc16_t crc16_t::null = { 0 };
const crc32_t crc32_t::null = { 0 };
const md5_t md5_t::null = { { 0 } };
const sha1_t sha1_t::null = { { 0 } };



//**************************************************************************
//  INLINE FUNCTIONS
//**************************************************************************

//-------------------------------------------------
//  char_to_hex - return the hex value of a
//  character
//-------------------------------------------------

inline int char_to_hex(char c)
{
	if (c >= '0' && c <= '9')
		return c - '0';
	if (c >= 'a' && c <= 'f')
		return 10 + c - 'a';
	if (c >= 'A' && c <= 'F')
		return 10 + c - 'A';
	return -1;
}



//**************************************************************************
//  SHA-1 HELPERS
//**************************************************************************

//-------------------------------------------------
//  from_string - convert from a string
//-------------------------------------------------

bool sha1_t::from_string(const char *string, int length)
{
	// must be at least long enough to hold everything
	memset(m_raw, 0, sizeof(m_raw));
	if (length == -1)
		length = strlen(string);
	if (length < 2 * sizeof(m_raw))
		return false;

	// iterate through our raw buffer
	for (int bytenum = 0; bytenum < sizeof(m_raw); bytenum++)
	{
		int upper = char_to_hex(*string++);
		int lower = char_to_hex(*string++);
		if (upper == -1 || lower == -1)
			return false;
		m_raw[bytenum] = (upper << 4) | lower;
	}
	return true;
}


//-------------------------------------------------
//  as_string - convert to a string
//-------------------------------------------------

const char *sha1_t::as_string(astring &buffer) const
{
	buffer.reset();
	for (int i = 0; i < ARRAY_LENGTH(m_raw); i++)
		buffer.catformat("%02x", m_raw[i]);
	return buffer;
}


//**************************************************************************
//  MD-5 HELPERS
//**************************************************************************

//-------------------------------------------------
//  from_string - convert from a string
//-------------------------------------------------

bool md5_t::from_string(const char *string, int length)
{
	// must be at least long enough to hold everything
	memset(m_raw, 0, sizeof(m_raw));
	if (length == -1)
		length = strlen(string);
	if (length < 2 * sizeof(m_raw))
		return false;

	// iterate through our raw buffer
	for (int bytenum = 0; bytenum < sizeof(m_raw); bytenum++)
	{
		int upper = char_to_hex(*string++);
		int lower = char_to_hex(*string++);
		if (upper == -1 || lower == -1)
			return false;
		m_raw[bytenum] = (upper << 4) | lower;
	}
	return true;
}


//-------------------------------------------------
//  as_string - convert to a string
//-------------------------------------------------

const char *md5_t::as_string(astring &buffer) const
{
	buffer.reset();
	for (int i = 0; i < ARRAY_LENGTH(m_raw); i++)
		buffer.catformat("%02x", m_raw[i]);
	return buffer;
}



//**************************************************************************
//  CRC-32 HELPERS
//**************************************************************************

//-------------------------------------------------
//  from_string - convert from a string
//-------------------------------------------------

bool crc32_t::from_string(const char *string, int length)
{
	// must be at least long enough to hold everything
	m_raw = 0;
	if (length == -1)
		length = strlen(string);
	if (length < 2 * sizeof(m_raw))
		return false;

	// iterate through our raw buffer
	m_raw = 0;
	for (int bytenum = 0; bytenum < sizeof(m_raw) * 2; bytenum++)
	{
		int nibble = char_to_hex(*string++);
		if (nibble == -1)
			return false;
		m_raw = (m_raw << 4) | nibble;
	}
	return true;
}


//-------------------------------------------------
//  as_string - convert to a string
//-------------------------------------------------

const char *crc32_t::as_string(astring &buffer) const
{
	return buffer.format("%08x", m_raw);
}


//-------------------------------------------------
//  append - hash a block of data, appending to
//  the currently-accumulated value
//-------------------------------------------------

void crc32_creator::append(const void *data, UINT32 length)
{
	m_accum.m_raw = crc32(m_accum, reinterpret_cast<const Bytef *>(data), length);
}



//**************************************************************************
//  CRC-16 HELPERS
//**************************************************************************

//-------------------------------------------------
//  from_string - convert from a string
//-------------------------------------------------

bool crc16_t::from_string(const char *string, int length)
{
	// must be at least long enough to hold everything
	m_raw = 0;
	if (length == -1)
		length = strlen(string);
	if (length < 2 * sizeof(m_raw))
		return false;

	// iterate through our raw buffer
	m_raw = 0;
	for (int bytenum = 0; bytenum < sizeof(m_raw) * 2; bytenum++)
	{
		int nibble = char_to_hex(*string++);
		if (nibble == -1)
			return false;
		m_raw = (m_raw << 4) | nibble;
	}
	return true;
}


//-------------------------------------------------
//  as_string - convert to a string
//-------------------------------------------------

const char *crc16_t::as_string(astring &buffer) const
{
	return buffer.format("%04x", m_raw);
}


//-------------------------------------------------
//  append - hash a block of data, appending to
//  the currently-accumulated value
//-------------------------------------------------

void crc16_creator::append(const void *data, UINT32 length)
{
	static const UINT16 s_table[256] =
	{
	    0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
	    0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
	    0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
	    0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
	    0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
	    0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
	    0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
	    0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
	    0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
	    0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
	    0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
	    0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
	    0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
	    0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
	    0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
	    0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
	    0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
	    0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
	    0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
	    0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
	    0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
	    0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
	    0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
	    0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
	    0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
	    0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
	    0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
	    0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
	    0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
	    0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
	    0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
	    0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
    };

	const UINT8 *src = reinterpret_cast<const UINT8 *>(data);

	// fetch the current value into a local and rip through the source data
	UINT16 crc = m_accum.m_raw;
	while (length-- != 0)
		crc = (crc << 8) ^ s_table[(crc >> 8) ^ *src++];
	m_accum.m_raw = crc;
}